U.S. patent number 10,741,791 [Application Number 16/705,743] was granted by the patent office on 2020-08-11 for display apparatus.
This patent grant is currently assigned to SAMSUNG DISPLAY CO., LTD.. The grantee listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to Yoongyeong Bae, Gyoowan Han, Inae Han, Seongchae Jeong, Hyojin Kim, Ilseob Yoon.
United States Patent |
10,741,791 |
Kim , et al. |
August 11, 2020 |
Display apparatus
Abstract
A display apparatus includes a substrate having a bending area
between a first area and a second area, wherein the substrate is
bent in the bending area, a display portion on an upper surface of
the substrate and positioned in the first area, and a protective
film on a lower surface of the substrate and including a protective
film base and an adhesive layer. The protective film base includes
a plurality of cavities.
Inventors: |
Kim; Hyojin (Yongin-si,
KR), Bae; Yoongyeong (Yongin-si, KR), Yoon;
Ilseob (Yongin-si, KR), Jeong; Seongchae
(Yongin-si, KR), Han; Inae (Yongin-si, KR),
Han; Gyoowan (Yongin-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
Yongin-si, Gyeonggi-do |
N/A |
KR |
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Assignee: |
SAMSUNG DISPLAY CO., LTD.
(Yongin-si, Gyeonggi-Do, KR)
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Family
ID: |
62489710 |
Appl.
No.: |
16/705,743 |
Filed: |
December 6, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200111994 A1 |
Apr 9, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15827600 |
Nov 30, 2017 |
10522785 |
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Foreign Application Priority Data
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Dec 8, 2016 [KR] |
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10-2016-0166881 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B
3/28 (20130101); B32B 27/281 (20130101); B32B
27/28 (20130101); B32B 27/32 (20130101); B32B
27/08 (20130101); B32B 27/365 (20130101); B32B
15/08 (20130101); H01L 51/5253 (20130101); B32B
27/308 (20130101); B32B 7/12 (20130101); B32B
15/20 (20130101); H01L 51/0097 (20130101); B32B
3/30 (20130101); B32B 27/286 (20130101); B32B
3/26 (20130101); G06F 1/16 (20130101); B32B
2250/44 (20130101); H01L 2251/566 (20130101); B32B
2307/202 (20130101); B32B 2457/206 (20130101); Y02E
10/549 (20130101); H01L 2251/5338 (20130101); B32B
2307/546 (20130101); G06F 1/1652 (20130101) |
Current International
Class: |
H01L
51/00 (20060101); B32B 3/30 (20060101); H01L
51/52 (20060101); B32B 7/12 (20060101); G06F
1/16 (20060101) |
Field of
Search: |
;361/749 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10-2014-0108914 |
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Sep 2014 |
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KR |
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10-2014-0123771 |
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Oct 2014 |
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KR |
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10-2015-0007632 |
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Jan 2015 |
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KR |
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10-2015-0036443 |
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Apr 2015 |
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KR |
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10-2015-0043604 |
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Apr 2015 |
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KR |
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10-2016-0108720 |
|
Sep 2016 |
|
KR |
|
Primary Examiner: Willis; Tremesha S
Attorney, Agent or Firm: F. Chau & Associates, LLC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser.
No. 15/827,600 filed on Nov. 30, 2017, which claims priority under
35 U.S.C. .sctn. 119 to Korean Patent Application No.
10-2016-0166881, filed on Dec. 8, 2016, in the Korean Intellectual
Property Office, the disclosures of which are incorporated by
reference herein in their entireties.
Claims
What is claimed is:
1. A display apparatus comprising: a flexible substrate having a
bending area between a first area and a second area, wherein the
flexible substrate is bent in the bending area; a display portion
on an upper surface of the flexible substrate and positioned in the
first area; a printed circuit board or an electronic chip on the
upper surface of the flexible substrate and positioned in the
second area; and a protective film on a lower surface of the
flexible substrate and positioned in the second area, the
protective film comprises a protective film base and an adhesive
layer, wherein the protective film base comprises a plurality of
cavities.
2. The display apparatus of claim 1, wherein the protective film
base comprises a first surface in contact with the adhesive layer,
wherein the plurality of cavities is inside the protective film
base and spaced apart from the first surface.
3. The display apparatus of claim 1, wherein the protective film
base comprises a first surface in contact with the adhesive layer,
wherein the first surface comprises a plurality of concave portions
protruded toward the protective film base, and the plurality of
cavities comprises spaces between the plurality of concave portions
and the adhesive layer.
4. The display apparatus of claim 1, wherein the protective film
base comprises an opening corresponding to the bending area.
5. The display apparatus of claim 1, wherein the protective film
base comprises a stress concentration area corresponding to the
bending area, wherein a thickness of the stress concentration area
is less than a thickness of an area near the stress concentration
area.
6. The display apparatus of claim 1, wherein the protective film
comprises: a first protective film base layer comprising a
plurality of first cavities; and a second protective film base
layer comprising a plurality of second cavities, wherein the first
protective film base layer is stacked on the second protective film
base layer.
7. The display apparatus of claim 6, wherein the adhesive layer is
between the flexible substrate and the first protective film base
layer, wherein the first protective film base layer comprises a
first surface in contact with the adhesive layer, and the second
protective film base layer comprises a second surface in contact
with the first protective film base layer.
8. The display apparatus of claim 7, wherein the first surface of
the first protective film base layer comprises a plurality of first
concave portions protruded toward the first protective film base
layer, and the plurality of first cavities comprises spaces between
the plurality of first concave portions and the adhesive layer.
9. The display apparatus of claim 7, wherein the second surface of
the second protective film base layer comprises a plurality of
second concave portions protruded toward the second protective film
base layer, and the plurality of second cavities comprises spaces
between the plurality of second concave portions and the first
protective film base layer.
10. The display apparatus of claim 7, wherein the first surface of
the first protective film base layer comprises a plurality of first
concave portions protruded toward the first protective film base
layer and extending in a first direction, and the plurality of
first cavities comprises spaces between the plurality of first
concave portions and the adhesive layer, and wherein the second
surface of the second protective film base layer comprises a
plurality of second concave portions protruded toward the second
protective film base layer and extending in a second direction, and
the plurality of second cavities comprises spaces between the
plurality of second concave portions and the first protective film
base layer.
11. The display apparatus of claim 10, wherein the first direction
and the second direction are different from each other.
12. The display apparatus of claim 7, wherein at least one of the
first protective film base layer or the second protective film base
layer comprises an opening corresponding to the bending area.
13. The display apparatus of claim 1, further comprising a cushion
layer disposed on a portion of the protective film base
corresponding to the display portion.
14. The display apparatus of claim 1, wherein the cavities include
air.
15. A display apparatus comprising: a flexible substrate including
a bending area between a first area and a second area, wherein the
flexible substrate is bent in the bending area; a display portion
on an upper surface of the flexible substrate and positioned in the
first area; a printed circuit board or an electronic chip on the
upper surface of the flexible substrate and positioned in the
second area; and a protective film on a lower surface of the
flexible substrate and positioned in the second area, the
protective film comprises a protective film base and an adhesive
layer, wherein the protective film base comprises a plurality of
cavities in the first area.
16. The display apparatus of claim 15, wherein a thickness of each
of the cavities is smaller than a thickness of the protective film
base.
17. The display apparatus of claim 15, wherein the cavities include
air.
18. The display apparatus of claim 15, wherein the plurality of
cavities overlap the bending area.
19. The display apparatus of claim 15, wherein the protective film
base comprises an opening corresponding to the bending area.
20. The display apparatus of claim 15, wherein the protective film
base comprises a stress concentration area corresponding to the
bending area, wherein a thickness of the stress concentration area
is less than a thickness of an area near the stress concentration
area.
Description
TECHNICAL FIELD
The present invention relates to a display apparatus.
DISCUSSION OF THE RELATED ART
In general, a display apparatus has a display portion arranged on a
substrate. By bending at least a part of the display apparatus, the
display portion may be viewed from various angles or a non-display
area of the display apparatus may be reduced.
However, defects may occur in the process of manufacturing a curved
display apparatus. Therefore, the lifetime of the curved display
apparatus may be reduced, and the manufacturing costs thereof may
increase.
SUMMARY
According to an exemplary embodiment of the present invention, a
display apparatus includes a substrate having a bending area
between a first area and a second area, wherein the substrate is
bent in the bending area, a display portion on an upper surface of
the substrate and positioned in the first area, and a protective
film on a lower surface of the substrate and including a protective
film base and an adhesive layer. The protective film base includes
a plurality of cavities.
In an exemplary embodiment of the present invention, the protective
film base includes a first surface in contact with the adhesive
layer. The plurality of cavities is inside the protective film base
and spaced apart from the first surface.
In an exemplary embodiment of the present invention, the protective
film base includes a first surface in contact with the adhesive
layer. The first surface includes a plurality of concave portions
protruded toward the protective film base, and the plurality of
cavities includes spaces between the plurality of concave portions
and the adhesive layer.
In an exemplary embodiment of the present invention, the protective
film base includes an opening corresponding to the bending
area.
In an exemplary embodiment of the present invention, the protective
film base includes a stress concentration area corresponding to the
bending area. A thickness of the stress concentration area is less
than a thickness of an area near the stress concentration area.
In an exemplary embodiment of the present invention, the protective
film includes a first protective film base layer including a
plurality of first cavities, and a second protective film base
layer including a plurality of second cavities. The first
protective film base layer is stacked on the second protective film
base layer.
In an exemplary embodiment of the present invention, the adhesive
layer is between the substrate and the first protective film base
layer. The first protective film base layer includes a first
surface in contact with the adhesive layer, and the second
protective film base layer includes a second surface in contact
with the first protective film base layer.
In an exemplary embodiment of the present invention, the first
surface of the first protective film base layer includes a
plurality of first concave portions protruded toward the first
protective film base layer, and the plurality of first cavities
includes spaces between the plurality of first concave portions and
the adhesive layer.
In an exemplary embodiment of the present invention, the second
surface of the second protective film base layer includes a
plurality of second concave portions protruded toward the second
protective film base layer, and the plurality of second cavities
includes spaces between the plurality of second concave portions
and the first protective film base layer.
In an exemplary embodiment of the present invention, the first
surface of the first protective film base layer includes a
plurality of first concave portions protruded toward the first
protective film base layer and extending in a first direction, and
the plurality of first cavities includes spaces between the
plurality of first concave portions and the adhesive layer. The
second surface of the second protective film base layer includes a
plurality of second concave portions protruded toward the second
protective film base layer and extending in a second direction, and
the plurality of second cavities includes spaces between the
plurality of second concave portions and the first protective film
base layer.
In an exemplary embodiment of the present invention, the first
direction and the second direction are different from each
other.
In an exemplary embodiment of the present invention, at least one
of the first protective film base layer or the second protective
film base layer includes an opening corresponding to the bending
area.
In an exemplary embodiment of the present invention, the display
apparatus of further includes a cushion layer disposed on a portion
of the protective film base corresponding to the display
portion.
In an exemplary embodiment of the present invention, the cavities
include air.
According to an exemplary embodiment of the present invention, a
display apparatus includes a substrate, a display portion on a
first surface of the substrate, and a protective film on a second
surface of the substrate and including a protective film base and
an adhesive layer, the protective film base includes a plurality of
air cavities.
In an exemplary embodiment of the present invention, the protective
film base includes a first surface in contact with the adhesive
layer. The plurality of cavities is inside the protective film base
and spaced apart from the first surface of the protective film
base.
In an exemplary embodiment of the present invention, the protective
film base includes a first surface in contact with the adhesive
layer. The first surface of the protective film base includes a
plurality of concave portions protruded toward the protective film
base, and the plurality of cavities includes spaces between the
plurality of concave portions and the adhesive layer.
In an exemplary embodiment of the present invention, the protective
film base includes a first protective film base layer including a
plurality of first cavities, and a second protective film base
layer including a plurality of second cavities. The first
protective film base layer is stacked on the second protective film
base layer.
In an exemplary embodiment of the present invention, the adhesive
layer is between the substrate and the first protective film base
layer. The first protective film base layer includes a first
surface in contact with the adhesive layer and the second
protective film base layer includes a second surface in contact
with the first protective film base layer. The first surface of the
first protective film base layer includes a plurality of first
concave portions protruded toward the first protective film base
layer, and the plurality of first cavities includes spaces between
the plurality of first concave portions and the adhesive layer. The
second surface of the second protective film base layer includes a
plurality of second concave portions protruded toward the second
protective film base layer, and the plurality of second cavities
includes spaces between the plurality of second concave portions
and the first protective film base layer.
According to an exemplary embodiment of the present invention, a
display apparatus includes a flexible substrate, a display portion
on an upper surface of the substrate, and a protective film on a
lower surface of the substrate and including a protective film base
and an adhesive layer. The protective film base includes a
plurality of cavities and a first area. A thickness of the
protective film base in the first area is different from a
thickness of the protective film base in a second area adjacent to
the first area.
In an exemplary embodiment of the present invention, the thickness
of the protective film base in the first area is less than the
thickness of the protective film base in a second area.
In an exemplary embodiment of the present invention, the protective
film base includes a first protective film base layer and a second
protective film base layer disposed on a portion of the first
protective film base layer. Only the first protective film base
layer extends throughout the first area and the second area.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features of the present invention will become
more apparent by describing in detail exemplary embodiments
thereof, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of a portion of a display apparatus
according to an exemplary embodiment of the present invention;
FIGS. 2 and 3 are cross-sectional views illustrating processes for
manufacturing the display apparatus of FIG. 1 according to an
exemplary embodiment of the present invention; and
FIGS. 4 to 8 are cross-sectional views illustrating cross-sectional
views of the display apparatus of FIG. 1 according to an exemplary
embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Hereinafter, exemplary embodiments of the present invention will be
described more fully with reference to the accompanying drawings.
When description is made with reference to the drawings, like
reference numerals in the drawings may denote like or corresponding
elements, and repeated descriptions thereof may be omitted.
As used herein, the singular forms "a" "an" and "the" are intended
to include the plural forms as well, unless the context clearly
indicates otherwise.
It will be understood that when a layer, region, or element is
referred to as being "formed on" or "disposed on", another layer,
region, or element, it can be directly on the other layer, region,
or element or intervening layers, regions or elements may be
present.
Sizes of elements in the drawings may be exaggerated for
convenience of explanation.
When a certain embodiment may be implemented differently, a
specific process order may be performed differently from the
described order. For example, two consecutively described processes
may be performed substantially at the same time or performed in an
order opposite to the described order.
It will be understood that when a layer, region, or component is
referred to as being "connected" to another layer, region, or
component, it may be "directly connected" to the other layer,
region, or component or may be "indirectly connected" to the other
layer, region, or component with other layer, region, or component
interposed therebetween. For example, it will be understood that
when a layer, region, or component is referred to as being
"electrically connected" to another layer, region, or component, it
may be "directly electrically connected" to the other layer,
region, or component or may be "indirectly electrically connected"
to other layer, region, or component with other layer, region, or
component interposed therebetween.
FIG. 1 is a perspective view of a portion of a display apparatus
according to an exemplary embodiment of the present invention.
According to the present embodiment, since a portion of a substrate
100, which is included in the display apparatus, is bent as shown
in FIG. 1, a portion of the display apparatus has a bent form in a
manner corresponding to the bend of the substrate 100.
As shown in FIG. 1, the substrate 100 included in the display
apparatus has a bending area BA which extends in a first direction
(e.g., +y direction). Along a second direction (e.g., +x direction)
crossing the first direction, the bending area BA is between a
first area 1A and a second area 2A. The substrate 100 is bent
around a bending axis BAX which extends in the first direction
(e.g., +y direction), as shown in FIG. 1. The substrate 100 may
include various materials having flexible or bendable
characteristics, and may include, for example, a polymer resin such
as polyethersulfone (PES), polyacrylate (PAR), polyetherimide
(PEI), polyethylene naphthalate (PEN), polyethylene terephthalate
(PET), polyphenylene sulfide (PPS), polyarylate, polyimide (PI),
polycarbonate (PC), or cellulose acetate propionate (CAP).
FIGS. 2 and 3 are cross-sectional views illustrating processes for
manufacturing the display apparatus of FIG. 1 according to an
exemplary embodiment of the present invention;
First, a display panel as shown in FIG. 2 is prepared. As shown in
FIG. 2, the first area 1A of the substrate 100 includes a display
area DA. In addition to the display area DA, the first area 1A
includes a portion of a non-display area outside the display area
DA, as shown in FIG. 2. The second area 2A includes a portion of
the non-display area. In the first area 1A, a display portion
including a display device, such as an organic light-emitting
device 300, and a thin film transistor 210 may be arranged. The
display portion may include only components arranged in the display
area DA, and may also include components that correspond to the
first area 1A but are arranged in the non-display area. The
substrate 100 has the bending area BA between the first area 1A and
the second area 2A. The substrate 100 is bent in the bending area
BA to have a curved shape, as shown in FIG. 1.
The display panel includes a protective film base 170 disposed on a
lower surface of the substrate 100 in a third direction (e.g., -z
direction). The protective film base 170 may be attached on the
lower surface of the substrate 100 by an adhesive layer 180. In
other words, a protective film, which includes the protective film
base 170, and the adhesive layer 180 is attached on the lower
surface of the substrate 100.
A detailed structure of the display panel with the protective film
attached thereon will be described with reference to FIG. 2.
In addition to the display device such as the organic
light-emitting device 300, the display area DA of the display panel
may include the thin film transistor 210 to which the organic
light-emitting device 300 is electrically connected, as described
above. In addition, a pixel electrode 310 of the organic
light-emitting device 300 is electrically connected to the thin
film transistor 210. A thin film transistor may also be arranged in
a peripheral area outside the display area DA of the substrate 100,
as needed. The thin film transistor arranged in the peripheral area
may be, for example, a portion of a circuit unit for controlling an
electrical signal applied to the display area DA.
The thin film transistor 210 may include a semiconductor layer 211
including amorphous silicon, polycrystalline silicon, or an organic
semiconductor material, a gate electrode 213, a source electrode
215a, and a drain electrode 215b. To secure insulation between the
semiconductor layer 211 and the gate electrode 213, a gate
insulating layer 120 including inorganic materials such as silicon
oxide, silicon nitride, and/or silicon oxynitride may be arranged
between the semiconductor layer 211 and the gate electrode 213. An
interlayer insulating layer 130 including inorganic materials such
as silicon oxide, silicon nitride, and/or silicon oxynitride may be
arranged on the gate electrode 213. The source electrode 215a and
the drain electrode 215b may be arranged on the interlayer
insulating layer 130. Insulating layers including inorganic
materials may be formed via chemical vapor deposition (CVD) or
atomic layer deposition (ALD). This forming method is also applied
to exemplary embodiments of the present invention and various
modifications thereof to be described below.
A buffer layer 110 may be arranged between the thin film transistor
210 and the substrate 100, as described above. The buffer layer 110
may include inorganic materials such as silicon oxide, silicon
nitride, and/or silicon oxynitride. The buffer layer 110 may
further flatten an upper surface of the substrate 100, or prevent
or reduce infiltration of impurities from the substrate 100, etc.
to the semiconductor layer 211 of the thin film transistor 210.
A planarization layer 140 may be arranged over the thin film
transistor 210. For example, when the organic light-emitting device
300 is arranged on the thin film transistor 210, as shown in FIG.
2, the planarization layer 140 may substantially planarize an upper
portion of the protective film covering the thin film transistor
210. The planarization layer 140 may include an organic material
such as acryl, benzocyclobutene (BCB), or hexamethyldisiloxane
(HMDSO). Although the planarization layer 140 is illustrated as a
single-layer in FIG. 2, the planarization layer 140 may be
variously modified. For example, the planarization layer 140 may
have a multi-layered structure. As shown in FIG. 2, the
planarization layer 140 may have an opening outside the display
area DA so that a portion of the planarization layer 140 in the
display area DA and a portion of the planarization layer 140 in the
second area 2A are physically separated from each other. For
example, the opening may correspond to the first area 1A. This
separation may prevent impurities infiltrating from the outside
from reaching the inside of the display area DA through the inside
of the planarization layer 140.
In the display area DA, the organic light-emitting device 300
including the pixel electrode 310, an opposite electrode 330, and
an intermediate layer 320 interposed therebetween and including an
emission layer, may be arranged on the planarization layer 140. The
pixel electrode 310 contacts any one of the source electrode 215a
and the drain electrode 215b via an opening formed in the
planarization layer 140, and the pixel electrode 310 may be
electrically connected to the thin film transistor 210, as shown in
FIG. 2.
A pixel-defining layer 150 may be arranged on the planarization
layer 140. The pixel-defining layer 150 has an opening
corresponding to each sub-pixel, and thus serves to form a pixel.
For example, the opening exposes at least a central portion of the
pixel electrode 310. In addition, as shown in FIG. 2, the
pixel-defining layer 150 may prevent an occurrence of an arc, etc.
on an edge of the pixel electrode 310 by increasing a distance
between the edge of the pixel electrode 310 and the opposite
electrode 330 above the pixel electrode 310. The pixel-defining
layer 150 may include, for example, organic materials such as PI
and HMDSO.
The intermediate layer 320 may include a low molecular weight
material or a high molecular weight (polymer) material. When the
intermediate layer 320 includes a low molecular weight material,
the intermediate layer 320 may have a structure in which a hole
injection layer (HIL), a hole transport layer (HTL), an emission
layer (EML), an electron transport layer (ETL), an electron
injection layer (EIL), etc. are stacked in a single or composite
structure, and may include various organic materials such as copper
phthalocyanine (CuPc),
N,N'-Di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB), and
tris-8-hydroxyquinoline aluminum (Alq3). The above-described layers
may be formed via a vacuum deposition method.
When the intermediate layer 320 includes a high molecular weight
material, the intermediate layer 320 may have a structure which
generally includes an HTL and an EML. In this case, the HTL may
include poly(3,4-ethylenedioxythiophene) (PEDOT) and the EML may
include a high molecular weight material such as
poly-phenylenevinylene (PPV) or polyfluorene. The intermediate
layer 320 may be formed via screen printing, inkjet printing, laser
induced thermal imaging (LITI), etc.
The intermediate layer 320 is not limited thereto and may have
various other structures. For example, the intermediate layer 320
may include an integrated layer covering a plurality of pixel
electrodes 310, and may also include a patterned layer
corresponding to each of the plurality of pixel electrodes 310.
The opposite electrode 330 may be arranged on a top portion of the
display area DA and cover the display area DA, as illustrated in
FIG. 2. In other words, the opposite electrode 330 may be
integrally formed in a plurality of organic light-emitting devices
300, and thus may correspond to the plurality of pixel electrodes
310.
Since the organic light-emitting device 300 may be damaged by
humidity, oxygen, or other external elements from the outside, an
encapsulation layer 400 may protect the organic light-emitting
device 300 by encapsulating the organic light-emitting device 300.
The encapsulation layer 400 may cover the display area DA and
extend to the outside of the display area DA. The encapsulation
layer 400 may include a first inorganic encapsulation layer 410, an
organic encapsulation layer 420, and a second inorganic
encapsulation layer 430, as shown in FIG. 2.
The first inorganic encapsulation layer 410 may cover the opposite
electrode 330 and may include silicon oxide, silicon nitride,
and/or silicon oxynitride, etc. Other layers such as a capping
layer may be arranged between the first inorganic encapsulation
layer 410 and the opposite electrode 330, as needed. Since the
first inorganic encapsulation layer 410 is formed along a structure
thereunder, an upper surface of the first inorganic encapsulation
layer 410 might not be flat, as shown in FIG. 2. The organic
encapsulation layer 420 may cover the first inorganic encapsulation
layer 410, and an upper surface of the organic encapsulation layer
420 may be substantially flat, unlike the first inorganic
encapsulation layer 410. For example, the upper surface of the
organic encapsulation layer 420 may be substantially flat in an
area corresponding to the display area DA. The organic
encapsulation layer 420 may include one or more of polyethylene
terephthalate, polyethylene naphthalate, polycarbonate, polyimide,
polyethylene sulfonate, polyoxymethylene, polyarylate, and
hexamethyldisiloxane. The second inorganic encapsulation layer 430
may cover the organic encapsulation layer 420 and may include
silicon oxide, silicon nitride, and/or silicon oxynitride, etc. The
second inorganic encapsulation layer 430 may prevent the organic
encapsulation layer 420 from being exposed to the outside by having
the second inorganic encapsulation layer 430 contact an edge
arranged outside the display area DA.
Since the encapsulation layer 400 includes the first inorganic
encapsulation layer 410, the organic encapsulation layer 420, and
the second encapsulation layer 430, even when a crack forms in the
encapsulation layer 400 through the multi-layered structure, the
crack might not be connected between the first inorganic
encapsulation layer 410 and the organic encapsulation layer 420 or
between the organic encapsulation layer 420 and the second
encapsulation layer 430. Thus, it may be possible to prevent or
minimize the formation of a route, by means of a crack, through
which humidity, oxygen or other impurities from the outside may
penetrate into the display area DA.
If necessary, a process of forming, on the encapsulation layer 400,
a touch electrode having various patterns for a touch screen
function or a touch protection layer for protecting the touch
electrode may be further performed.
The display panel includes the protective film base 170 disposed on
the lower surface of the substrate 100 in the third direction
(e.g., -z direction). The protective film base 170 included in the
protective film may include polyethylene terephthalate (PET) or
polyimide (PI). As described above, the protective film base 170
may be attached on the lower surface of the substrate 100 by the
adhesive layer 180. The adhesive layer 180 included in the
protective film may include, for example, a pressure sensitive
adhesive (PSA). The time for attaching the protective film to the
lower surface of the substrate 100 may vary depending on the
situation.
For example, when a plurality of display portions is formed on a
single mother substrate, a rigid carder substrate may be positioned
under the mother substrate to facilitate handling of the mother
substrate having flexible or bendable characteristics during
manufacturing processes. In a state in which the mother substrate
is supported by the carrier substrate, a plurality of display
portions and encapsulation layers 400 for encapsulating the
plurality of display portions are formed on the mother substrate.
Each of the plurality of display portions includes a display device
such as the organic light-emitting device 300, the thin film
transistor 210, and the like, as described above. After the
plurality of display portions are formed on the mother substrate,
the carrier substrate may be separated from the mother substrate.
In addition, after a touch electrode and/or a touch protection
layer for protecting the touch electrode are also formed on the
encapsulation layers 400, the carrier substrate may be separated
from the mother substrate. In this case, the carrier substrate may
be separated from the mother substrate through, for example, a
physical or laser method. In any case, after the carrier substrate
is separated from the mother substrate, a protective film including
the protective film base 170 and the adhesive layer 180 may be
attached on a surface of the mother substrate in the direction of
the carrier substrate, and then a plurality of display panels may
be obtained by cutting the mother substrate and the protective
film. The plurality of display panels may be obtained from the
mother substrate through a physical cutting method using a tool
such as a blade, or a laser cutting method. The substrate 100 may
be understood as a state in which the mother substrate is cut in
such a manner previously described.
After the mother substrate and the protective film are cut to
obtain a plurality of display panels, a polarizing plate 520 may be
attached on the encapsulation layer 400 by an optically clear
adhesive (OCA) 510, and a printed circuit board, an electronic
chip, or the like may be attached to the second area 2A, as needed.
If an element such as a touch electrode or a touch protection layer
is on the encapsulation layer 400, the OCA 510 and the polarizing
plate 520 are positioned on the element. In addition, a bending
protection layer (BPL) 600 may be formed outside the display area
DA. For example, the bending protection layer 600 may be formed on
the planarization layer 140.
One display portion may be formed on one substrate 100 without
simultaneously obtaining a plurality of display panels by using a
mother substrate. Also in this case, a rigid carrier substrate may
be placed under the substrate 100 to facilitate handling of the
substrate 100 having flexible or bendable characteristics during
manufacturing processes. After a display portion and the
encapsulation layers 400 for encapsulating the display portion are
formed on the substrate 100, a carrier substrate may be separated
from the substrate 100. In addition, after a touch electrode and/or
a touch protection layer for protecting the touch electrode are
also formed on the encapsulation layers 400, the carrier substrate
may be separated from the substrate 100. In any case, after the
carrier substrate is separated from the substrate 100, a protective
film including the protective film base 170 and the adhesive layer
180 may be attached on a surface of the substrate 100. Then, the
polarizing plate 520 may be attached on the encapsulation layer 400
or the touch protection layer by the OCA 510, and if necessary, a
printed circuit board, an electronic chip, or the like may be
attached to the second area 2A. In addition, the bending protection
layer 600 may be formed outside the display area DA.
The polarizing plate 520 may reduce external light reflection. For
example, when external light passes through the polarizing plate
520 and then passes through the polarizing plate 520 again after
being reflected from an upper surface of the opposite electrode
330, the phase of the external light may be changed as the external
light passes through the polarizing plate 520 twice. As a result,
the phase of the reflected light becomes different from the phase
of the external light entering the polarizing plate 520, so that
destructive interference is generated, and consequently, visibility
may be increased by the reduction of external light reflection. The
OCA 510 and the polarizing plate 520 may be positioned to cover an
opening of the planarization layer 140, for example, as shown in
FIG. 2.
When manufacturing the display apparatus according to the present
embodiment, an operation of forming the polarizing plate 520 is not
always required, and other configurations other than the polarizing
plate 520 may be used. For example, a black matrix and a color
filter may be formed without attaching the polarizing plate 520,
thereby reducing external light reflection in a display apparatus
completed later.
The bending protection layer 600 may be positioned on a first
conductive layer 215c to correspond to at least the bending area
BA. For example, the bending protection layer 600 may overlap the
bending area BA. When a stack structure is bent, a stress neutral
plane exists in the stack structure. For example, if the bending
protection layer 600 is not disposed in the display apparatus, an
excessive tensile stress may be applied to the first conductive
layer 215c in the bending area BA in accordance with bending of the
substrate 100 or the like, as described later. This excessive
tensile stress may be applied because the position of the first
conductive layer 215c might not correspond to the stress neutral
plane. However, by forming the bending protection layer 600 and
adjusting the thickness and modulus of the bending protection layer
600, the position of the stress neutral plane may be adjusted in a
stack structure including the substrate 100, the first conductive
layer 215c, and the bending protection layer 600. By adjusting the
thickness and the modulus of the bending protection layer 600, the
position of the plane may be adjusted. Therefore, by placing the
stress neutral plane in the vicinity of the first conductive layer
215c through the bending protection layer 600, a tensile stress
applied to the first conductive layer 215c may be reduced to
protect a bending portion.
The bending protection layer 600 may extend to the edge of the
substrate 100 of the display apparatus, as shown in FIG. 2. For
example, the first conductive layer 215c, a second conductive layer
213b, and/or other conductive layers electrically connected to the
first and second conductive layers 215c and 213b in the second area
2A might not be covered, at least partially, by the interlayer
insulating layer 130 or the planarization layer 140, and may be
electrically connected to various electronic elements, a printed
circuit board, or the like. Accordingly, a portion of the display
apparatus (e.g., an electrically connected portion), in which the
first conductive layer 215c, the second conductive layer 213b,
and/or other conductive layers electrically connected to the first
and second conductive layers 215c and 213b are electrically
connected to various electronic elements, a printed circuit board,
or the like, is present. In this case, it may be useful to protect
the electrically connected portion from impurities such as moisture
from the outside, and the bending protection layer 600 may extend
to cover the electrically connected portion. Thus, by allowing the
bending protection layer 600 to cover the electrically connected
portion, the bending protection layer 600 may also serve as a
protective layer. In addition, the bending protection layer 600 may
extend to the edge of the substrate 100 of the display
apparatus.
FIG. 2 shows that an upper surface of the bending protection layer
600 in, for example, a negative second direction (e.g., -x
direction) of the display area DA is aligned with an upper surface
of the polarizing plate 520. However, the present invention is not
limited thereto. For example, an end portion of the bending
protection layer 600 in the negative second direction (e.g., -x
direction) of the display area DA may cover a portion of an upper
surface of an edge portion of the polarizing plate 520. In
addition, the end portion of the bending protection layer 600 in
the negative second direction (e.g., -x direction) of the display
area DA might not be in contact with the polarizing plate 520
and/or the OCA 510.
After the protective film including the protective film base 170
and the adhesive layer 180 is attached on the lower surface of the
substrate 100, a laser beam is radiated to at least a portion of
the protective film base 170 corresponding to the bending area BA
so that the protective film base 170 has an opening 170OP
corresponding to the bending area BA, as shown in FIG. 3.
A method of removing a portion of the protective film base 170
included in the protective film to form the opening 170OP is not
limited thereto. For example, at least a portion of the protective
film base 170 may be precut at the boundary between a portion to be
removed and a portion not to be removed of the protective film base
170 before the protective film is attached to the lower surface of
the substrate 100. Here, the portion of the protective film base
170 to be removed may be understood as a portion of the protective
film base 170 corresponding to the bending area BA when the
protective film is attached to the lower surface of the substrate
100. After the protective film is attached to the lower surface of
the substrate 100, the portion of the protective film base 170
corresponding to the bending area BA may be removed. In this case,
to remove the portion of the protective film base 170 corresponding
to the bending area BA, an adhesive strength of a portion of the
adhesive layer 180 corresponding to the portion of the protective
film base 170 corresponding to the bending area BA may be weaker
than an adhesive strength of the other portions of the adhesive
layer 180. In other words, the adhesive strength of the portion of
the adhesive layer 180 corresponding to the bending area BA may be
lower than the adhesive strength of the other portions of the
adhesive layer 180.
FIG. 3 is a cross-sectional view illustrating a portion of the
display apparatus of FIG. 1, specifically, the substrate 100 and
the protective film. As shown in FIG. 3, the substrate 100 may be
bent in the bending area BA. The protective film base 170 of the
protective film may protect the lower surface of the substrate 100,
and may have its own rigidity. Accordingly, when the flexibility of
the protective film base 170 is low, desquamation may occur between
the protective film base 170 and the substrate 100 as the substrate
100 is bent. However, in the case of the display apparatus
according to the present embodiment, since the protective film base
170 has the opening 170OP corresponding to the bending area BA, it
is possible to prevent the occurrence of the desquamation.
In FIG. 3, the edge of the substrate 100 in the second area 2A is
shown as coinciding with the end of the protective film. However,
the present invention is not limited thereto. For example, the ends
of the protective film base 170 and the adhesive layer 180 may not
extend to the edge of the substrate 100 and may not cover a lower
surface of the substrate 100 in the vicinity of the edge thereof.
In addition, in FIG. 3, an end surface (e.g., a side surface) of
the protective film base 170 is shown as being substantially
perpendicular to the lower surface of the substrate 100. However,
the end surface of the protective film base 170 may be inclined at
an angle not perpendicular to the lower surface of the substrate
100.
The buffer layer 110, the gate insulating layer 120, and the
interlayer insulating layer 130, which include an inorganic
material, shown in FIG. 2 may be collectively referred to as an
inorganic insulating layer. The inorganic insulating layer has an
opening corresponding to the bending area BA, as shown in FIG. 2.
In other words, the buffer layer 110, the gate insulating layer
120, and the interlayer insulating layer 130 may have respectively
openings 110a, 120a, and 130a corresponding to the bending area BA.
For example, that an opening corresponds to the bending area BA may
be understood as that the opening overlaps the bending area BA. In
this case, the area of the opening (e.g. 110a, 120a, and 130a) may
be larger than the area of the bending area BA. To this end, in
FIG. 2, a width OW of the opening is shown to be greater than the
width of the bending area BA. In this case, the area of the opening
may be the area of the smallest one of the openings 110a, 120a, and
130a of the buffer layer 110, the gate insulating layer 120, and
the interlayer insulating layer 130. In FIG. 2, for example, the
area of the opening is the area of the opening 110a of the buffer
layer 110.
In FIG. 2, the inner surface of the opening 110a of the buffer
layer 110 coincides with the inner surface of the opening 120a of
the gate insulating layer 120. However, the present invention is
not limited thereto. For example, the area of the opening 120a of
the gate insulating layer 120 may be larger than the area of the
opening 110a of the buffer layer 110. In addition, in this case,
the area of the opening may be the area of the smallest one of the
openings 110a, 120a, and 130a of the buffer layer 110, the gate
insulating layer 120, and the interlayer insulating layer 130.
When forming the display portion as described above, an organic
material layer 160 filling at least a portion of an opening of the
inorganic insulating layer is formed. In FIG. 2, the organic
material layer 160 is shown as filling the opening. The display
portion includes the first conductive layer 215c, and the first
conductive layer 215c may extend from the first area 1A to the
second area 2A through the bending area BA and may be positioned on
the organic material layer 160. In an area where the organic
material layer 160 is not present, the first conductive layer 215c
may be positioned on the inorganic insulating layer such as the
interlayer insulating layer 130. The first conductive layer 215c
may include the same material as the source electrode 215a and the
drain electrode 215b and may be formed simultaneously with the
source electrode 215a and the drain electrode 215b.
As described above, after the opening 170OP is formed in the
protective film base 170, the display panel is bent in the bending
area BA, as shown in FIG. 3. In this case, a tensile stress may be
applied to the first conductive layer 215c while the substrate 100
is bent in the bending area BA. However, in the case of the display
apparatus according to the present embodiment, it is possible to
prevent or reduce the occurrence of defects at the first conductive
layer 215c during a bending process.
If the inorganic insulating layer such as the buffer layer 110, the
gate insulating layer 120 and/or the interlayer insulating layer
130 does not have an opening in the bending area BA and has a
continuous shape from the first area 1A to the second area 2A and
the first conductive layer 215c is positioned on the inorganic
insulating layer, a high tensile stress is applied to the first
conductive layer 215c in the process of bending the substrate 100
or the like. For example, since the inorganic insulating layer has
a higher hardness than an organic material layer, the inorganic
insulating layer has a high probability of cracking in the bending
area BA. When a crack occurs in the inorganic insulating layer, a
crack may also occur in the first conductive layer 215c on the
inorganic insulating layer, and thus, the probability of the
occurrence of defects such as disconnection of the first conductive
layer 215c may be extremely high.
However, as described above, in the display apparatus according to
the present embodiment, the inorganic insulating layer has an
opening in the bending area BA, and a portion of the first
conductive layer 215c in the bending area BA is positioned on the
organic material layer 160 filling at least a portion of an opening
of the inorganic insulating layer. Since the inorganic insulating
layer has an opening in the bending area BA, the probability of the
occurrence of a crack in the inorganic insulating layer is
extremely low. In the case of the organic material layer 160 being
positioned in the opening of the inorganic insulating layer, the
probability of the occurrence of a crack is low due to
characteristics of an organic material included in the organic
material layer 160. Therefore, it is possible to prevent the
occurrence of a crack or reduce the probability of the occurrence
of a crack in the bending area BA of the first conductive layer
215c positioned on the organic material layer 160. Since the
hardness of the organic material layer 160 is lower than that of an
inorganic material layer (e.g., the inorganic insulating layer), a
tensile stress generated by the bending of the substrate 100 may be
absorbed by the organic material layer 160, and thus, it is
possible to effectively minimize concentration of a tensile stress
on the first conductive layer 215c.
The inorganic insulating layer might not have an opening. For
example, among components of the inorganic insulating layer, the
buffer layer 110 is integrally formed over the first area 1A, the
bending area BA, and the second area 2A without an opening, and
only the gate insulating layer 120 and the interlayer insulating
layer 130 may have the opening 120a and the opening 130a,
respectively. In this case, it may be understood that the inorganic
insulating layer does not have an opening but has a groove
extending to a surface of the buffer layer 110, and it may be
understood that the organic material layer 160 described above is
positioned to fill a groove in the inorganic insulating layer.
When forming the display portion, second conductive layers 213a and
213b may be formed in addition to the first conductive layer 215c.
The second conductive layers 213a and 213b may be formed in the
first area 1A or the second area 2A so as to be positioned in a
layer different from a layer in which the first conductive layer
215c is positioned, and may be electrically connected to the first
conductive layer 215c. In FIG. 2, the second conductive layers 213a
and 213b is shown as being formed in the same layer as the gate
electrode 213 of the thin film transistor 210. In other words, the
second conductive layers 213a and 213b may be formed on the gate
insulating layer 120, by using the same material as the gate
electrode 213 of the thin film transistor 210. In addition, the
first conductive layer 215c is shown as being in contact with the
second conductive layers 213a and 213b through contact holes formed
in the interlayer insulating layer 130. The second conductive layer
213a is shown as being positioned in the first area 1A, and the
second conductive layer 213b is shown as being positioned in the
second area 2A.
The second conductive layer 213a positioned in the first area 1A
may be electrically connected to a thin film transistor and the
like in the display area DA, and accordingly, the first conductive
layer 215c may be electrically connected to the thin film
transistor or the like in the display area DA through the second
conductive layer 213a. The second conductive layer 213b positioned
in the second area 2A may also be electrically connected to a thin
film transistor and the like in the display area DA by the first
conductive layer 215c. In this manner, the second conductive layers
213a and 213b may be electrically connected to components
positioned in the display area DA while being positioned outside
the display area DA, or the second conductive layers 213a and 213b
may extend in the direction of the display area DA while being
positioned outside the display area DA, so that at least a portion
of each of the second conductive layers 213a and 213b may be
positioned in the display area DA.
As described above, after the opening 170OP is formed in the
protective film base 170, the display panel may be bent in the
bending area BA, as shown in FIG. 3. In this case, a tensile stress
may be applied to components positioned in the bending area BA
while the substrate 100 is bent in the bending area BA.
Therefore, when the first conductive layer 215c traversing the
bending area BA is formed to include a material having a high
elongation, the occurrence of a crack in the first conductive layer
215c and defects such as disconnection of the first conductive
layer 215c may be prevented. In addition, in the first area 1A or
the second area 2A, the second conductive layers 213a and 213b may
be formed of a material having an elongation lower than that of the
first conductive layer 215c but having an electrical/physical
characteristic different from that of the first conductive layer
215c. Thus, the efficiency of electrical signal transmission in the
display apparatus may be increased, or the rate of failure
occurrence in a manufacturing process for the display apparatus may
be reduced. For example, the second conductive layers 213a and 213b
may include molybdenum, and the first conductive layer 215c may
include aluminum. The first conductive layer 215c or the second
conductive layers 213a and 213b may have a multilayered
structure.
In the case of the second conductive layer 213b positioned in the
second area 2A, at least a portion of the upper surface of the
second conductive layer 213b may be exposed to the outside without
being covered with the planarization layer 140, and thus, may be
electrically connected to various electronic elements or a printed
circuit board.
As shown in FIG. 2, the organic material layer 160 may have an
uneven surface 160a in at least a portion of the upper surface
thereof (e.g., in the +z direction). For example, the uneven
surface 160a may have grooves or a wave-like shape. Since the
organic material layer 160 has the uneven surface 160a, the upper
surface and/or the lower surface of the first conductive layer 215c
positioned on the organic material layer 160 may have a shape
corresponding to the uneven surface 160a of the organic material
layer 160.
As described above, a tensile stress may be applied to the first
conductive layer 215c when the substrate 100 is bent in the bending
area BA in a manufacturing process, and, the amount of the tensile
stress applied to the first conductive layer 215c may be reduced by
making the upper surface and/or the lower surface of the first
conductive layer 215c have a shape corresponding to the uneven
surface 160a of the organic material layer 160. In other words, a
tensile stress that may occur in the bending process may be reduced
through the deformation of the shape of the organic material layer
160 having a low rigidity. In this case, by deforming the shape of
the first conductive layer 215c, which has an uneven shape at least
before bending, so as to correspond to the shape of the organic
material layer 160 deformed by bending, the occurrence of defects
such as disconnection in the first conductive layer 215c may be
effectively prevented.
In addition, by forming the uneven surface 160a in at least a
portion of the upper surface (e.g., in the +z direction) of the
organic material layer 160, a surface area of the upper surface of
the organic material layer 160 and a surface area of the upper and
lower surface of the first conductive layer 215c may be increased.
For example, in an opening, the surface area of the upper surface
of the organic material layer 160 and the surface area of the upper
and lower surface of the first conductive layer 215c may be
increased. Large surface areas of the upper surface of the organic
material layer 160 and the upper and lower surface of the first
conductive layer 215c provide a large margin for deforming the
shape of the substrate 100 to reduce a tensile stress occurring due
to bending of the substrate 100.
Since the first conductive layer 215c is positioned on the organic
material layer 160, the lower surface of the first conductive layer
215c has a shape corresponding to the uneven surface 160a of the
organic material layer 160. In addition, the upper surface of the
first conductive layer 215c may have an uneven surface having a
unique shape that does not correspond to the uneven surface 160a of
the organic material layer 160. For example, the uneven surface of
the first conductive layer 215c may have grooves that do not
correspond to grooves of the uneven surface 160a of the organic
material layer 160. However, the present invention is not limited
thereto.
The uneven surface 160a of the upper surface of the organic
material layer 160 may be formed by various methods. For example,
in the case of forming the organic material layer 160, particular
portions thereof may be etched more than the other portions by
varying the amount of exposure of various portions of the organic
material layer 160, of which the upper surface is still flat in the
manufacturing process, by using a photoresist material and a slit
or halftone mask. In this case, more etched portions may be
understood as concave portions in the upper surface of the organic
material layer 160. A method of forming the uneven surface 160a is
not limited to the method described above. For example, various
methods, such as dry-etching and removing only specific portions of
the organic material layer 160 after the organic material layer 160
having a substantially flat upper surface is formed, may be
used.
To make the organic material layer 160 have the uneven surface 160a
in the upper surface, the upper surface of the organic material
layer 160 may have a plurality of grooves extending in the first
direction (e.g., +y direction). In this case, the shape of the
upper surface of the first conductive layer 215c positioned on the
organic material layer 160 corresponds to the shape of the upper
surface of the organic material layer 160. For example, the upper
surface of the first conductive layer 215c may have a plurality of
grooves extending in the first direction.
The organic material layer 160 may have the uneven surface 160a
only in an opening of the inorganic insulating layer. In FIG. 2, a
width UEW of a portion of the opening of the inorganic insulating
layer in which the uneven surface 160a of the organic material
layer 160 is formed is shown as being less than a width OW of the
opening of the inorganic insulating layer. If the organic material
layer 160 has an uneven surface 160a inside and outside the opening
of the inorganic insulating layer, the organic material layer 160
has the uneven surface 160a near an inside surface of the opening
110a of the buffer layer 110, an inside surface of the opening 120a
of the gate insulating layer 120, or an inside surface of the
opening 130a of the interlayer insulating layer 130. The organic
material layer 160 is relatively thinner in a concave portion of
the uneven surface 160a than in a protruding portion, and thus,
when the concave portion is positioned near the inside surface of
the opening 110a of the buffer layer 110, the inside surface of the
opening 120a of the gate insulating layer 120, or the inside
surface of the opening 130a of the interlayer insulating layer 130,
the organic material layer 160 may be disconnected without being
continuously connected. Accordingly, the organic material layer 160
may have the uneven surface 160a only in the opening of the
inorganic insulating layer so that the organic material layer 160
is prevented from being disconnected near the inner surface of the
opening 110a of the buffer layer 110, the inner surface of the
opening 120a of the gate insulating layer 120, or the inside
surface of the opening 130a of the interlayer insulating layer 130.
In other words, the uneven surface 160a of the organic material
layer 160 may have a width substantially equal to the width
UEW.
To prevent disconnection of the first conductive layer 215c in the
bending area BA, as described above, the organic material layer 160
may have an uneven surface 160a in the bending area BA. As a
result, the area of a portion having the uneven surface 160a in the
organic material layer 160 may be larger than the area of the
bending area BA but smaller than the area of the opening. In FIG.
2, the width UEW of the portion having the uneven surface 160a is
shown as being greater than the width of the bending area BA and
less than the width OW of the opening.
If at least one of the buffer layer 110, the gate insulating layer
120, and the interlayer insulating layer 130 includes an organic
insulating material, the organic material layer 160 may be formed
simultaneously with the at least one layer including the organic
insulating material. Furthermore, the at least one layer including
the organic insulating material and the organic material layer 160
may be integrally formed with each other. Examples of the organic
insulating material include polyethylene terephthalate,
polyethylene naphthalate, polycarbonate, polyimide, polyethylene
sulfonate, polyoxymethylene, polyarylate, and
hexamethyldisiloxane.
Most of the configurations described with reference to FIG. 2 may
be applied to exemplary embodiments of the present invention and
modifications to be described later.
As described above, the protective film including the protective
film base 170 and the adhesive layer 180 may be attached on the
lower surface of the substrate 100. In this case, the protective
film base 170 may include a plurality of cavities B. The protective
film base 170 included in the protective film may include
polyethyleneterephthalate (PET) or polyimide (PI). The plurality of
cavities B included in the protective film base 170 are spaces for
trapping air by bubbles having a predetermined size or more, formed
inside the protective film base 170. The sizes of the plurality of
cavities B may be determined depending on the thickness of the
protective film base 170. In an exemplary embodiment of the present
invention, when the protective film base 170 has a thickness of
about 70 um to about 80 um, each of the plurality of cavities B may
have a diameter of about 1 um to about 75 um. However, this is only
an example, and the sizes of the plurality of cavities B may be
changed depending on the thickness of the protective film base 170.
When the sizes of the plurality of cavities B are less than 1 um,
it may not be possible to obtain a sufficient external shock
mitigation effect. In FIG. 3, a plurality of cavities B may be
arranged in one row in the protective film base 170 as shown, but
the present disclosure is not limited thereto. The plurality of
cavities B may be arranged in one row as in FIG. 3, or may be
arranged in a plurality of rows. In an exemplary embodiment of the
present invention, the plurality of cavities B may be irregularly
arranged inside the protective film base 170. For example, the
plurality of cavities B may have a staggered arrangement inside of
the protective film base 170. As the protective film base 170
includes the plurality of cavities B for trapping air, the
protective film base 170 may mitigate an impact that may occur in
the process of manufacturing the display apparatus. The plurality
of cavities B may provide a force buffering effect to disperse an
external impact, transmitted in one direction through a space for
trapping air, in various directions.
The protective film base 170 may include a first surface M1 in
contact with the adhesive layer 180, and the plurality of cavities
B may be arranged in the inside of the protective film base spaced
apart from the first surface M1. The plurality of cavities B may be
formed by radiating a laser beam to the protective film base 170
before the protective film is attached to the lower surface of the
substrate 100. The plurality of cavities B may be formed through
heat generated from the laser beam radiated to the protective film
base 170. The shapes of the plurality of cavities B may be
determined depending on the type and settings of laser. The
plurality of cavities B may be substantially circular, but may be
formed in a shape different from the circular shape by using a
laser. The laser may be a femto-second IR laser or a pico-second IR
laser. In an exemplary embodiment of the present invention, the
plurality of cavities B may be formed in the inside spaced apart
from the first surface M1 by positioning a spot of a laser inside
the protective film base 170 and radiating a laser beam. In an
exemplary embodiment of the present invention, the plurality of
cavities B may be formed by attaching the protective film to the
lower surface of the substrate 100 and then radiating a laser beam
to the protective film base 170. In an exemplary embodiment of the
present invention, the plurality of cavities B may be formed in the
protective film base 170 by using a foaming process when the
protective film is manufactured. In this case, the plurality of
cavities B may be irregularly formed inside the protective film
base 170.
As described above, the display apparatus according to the present
embodiment may mitigate an external impact, which may occur in the
manufacture of a display apparatus having a bent portion, through a
protective film including a plurality of cavities B.
FIGS. 4 to 8 are cross-sectional views illustrating cross-sectional
views of the display apparatus of FIG. 1 according to an exemplary
embodiment of the present invention.
Referring to FIG. 4, a protective film base 170 may include a
plurality of cavities B for trapping air. In this case, the
protective film base 170 may have a stress concentration area 170A
corresponding to the bending area BA. Although FIG. 3 shows a case
where the protective film base 170 includes an opening 170OP
corresponding to the bending area BA, the present disclosure is not
limited thereto. As in FIG. 4, the protective film base 170 may
include the stress concentration area 170A corresponding to the
bending area BA. The protective film base 170 may include a
plurality of cavities B in the stress concentration area 170A as
well as in a peripheral area corresponding to a first area 1A and a
second area 2A. When the display apparatus is bent, a tensile
stress may be applied to the bending area BA. Although the opening
170OP may be formed in the protective film base 170 to reduce the
tensile stress, as shown in FIG. 3, exemplary embodiments of the
present invention may include a plurality of cavities B also in the
stress concentration area 170A to reduce the tensile stress. The
plurality of cavities B are spaces for trapping air therein, and
may absorb stress generated during bending or disperse the
direction of a force, thereby reducing the tensile stress. A
thickness t2 of the protective film base 170 in the stress
concentration area 170A may be less than a thickness t1 of the
protective film base 170 in a peripheral area around the stress
concentration area 170A. As the thickness t2 of the protective film
base 170 in the stress concentration area 170A is less than the
thickness t1 of the protective film base 170 in the peripheral
area, the protective film base 170 may reduce the tensile
stress.
In an alternative embodiment of the present invention, in the
stress concentration area 170A of the protective film base 170,
there may be a plurality of openings.
In FIG. 4, a plurality of cavities B arranged in the stress
concentration area 170A and a plurality of cavities B arranged in
the peripheral area around the stress concentration area 170A are
shown to have substantially the same size and shape. However, the
present invention is not limited thereto, and the plurality of
cavities B arranged in the stress concentration area 170A may have
different sizes and/or shapes from the plurality of cavities B
arranged in the peripheral area. For example, since the protective
film base 170 in the stress concentration area 170A has a smaller
thickness than that of in the peripheral area, the plurality of
cavities B arranged in the stress concentration area 170A may be
smaller in size than the plurality of cavities B arranged in the
peripheral area. In addition, the plurality of cavities B arranged
in the peripheral area are arranged in a plurality of rows, whereas
a plurality of cavities B arranged in the stress concentration area
170A may be arranged in a single column.
Referring to FIG. 5, in a display apparatus according to an
exemplary embodiment of the present invention, after a substrate
100 is bent, a cushion layer 190 may be arranged in an area where a
first area 1A and a second area 2A face each other. In other words,
the cushion layer 190 may be disposed where it contacts a portion
of the protective film base 170 in the first area 1A and a portion
of the protective film base 170 in the second area 2A. The cushion
layer 190 may support a display panel, arranged in a space in which
the first area 1A and the second area 2A are spaced apart from each
other after the substrate 100 is bent, and may absorb an impact.
The cushion layer 190 may include a material having elasticity.
In an alternative embodiment of the present invention, the cushion
layer 190 may be disposed on at least a portion of the protective
film base 170 that corresponds to the display area DA.
A filler may be further arranged in an opening portion 170OP of a
protective film. The filler may be formed by injecting a liquid or
paste material into the opening 170OP of the protective film and
curing the liquid or paste material. To cure the filler, a method
of radiating ultraviolet rays (UV) or applying heat may be used.
The filler may include a material having adhesion properties, and
may prevent or reduce deformation of the substrate 100 due to a
restoring force for restoring the substrate 100 to a state before
the bending of the substrate 100 as the filler is cured by UV or
heat. The cushion layer 190 and/or the filler may be omitted or
only one of them may be used.
Referring to FIG. 6, a plurality of cavities B may be formed on one
side of a protective film base 170. In other words, the protective
film base 170 may include a first surface M1 in contact with an
adhesive layer 180, and the first surface M1 may include a
plurality of concave portions concaved in the direction of the
protective film base 170. In this case, the plurality of cavities B
may be spaces between the plurality of concave portions and an
adhesive layer 180. In FIG. 6, a laser beam may be radiated to the
first surface M1 of the protective film base 170 to form the
plurality of cavities B. A laser for radiating the laser beam may
be a femto-second IR laser or a pico-second IR laser, as described
above. The plurality of concave portions may be formed by radiating
a laser beam to the first surface M1 of the protective film base
170, and in this case, the plurality of concave portions may be
concavely formed in the direction of the protective film base 170
by using a radiated laser heat. And then, the plurality of cavities
B may be formed in the protective film base 170 by stacking the
adhesive layer 180 on the first surface M1 of the protective film
base 170 to form a protective film.
FIG. 6 shows a case where the protective film base 170 includes a
stress concentration area 170A corresponding to a bending area BA.
In FIG. 6, the sizes and shapes of the plurality of cavities B
arranged in the stress concentration area 170A are the same as
those of a plurality of cavities B arranged in a peripheral area.
However, the present invention is not limited thereto. The sizes
and/or shapes of the plurality of cavities B arranged in the stress
concentration area 170A may be different from the sizes and/or
shapes of the plurality of cavities B arranged in the peripheral
area. For example, the sizes of the plurality of cavities B
arranged in the stress concentration area 170A may be smaller than
the sizes of the plurality of cavities B arranged in the peripheral
area. In addition, cavities B formed as spaces between a plurality
of concave portions of the protective film base 170 and the
adhesive layer 180 may be arranged in the stress concentration area
170A, and the peripheral area may include circular cavities B
formed therein as well as cavities B formed as spaces between the
plurality of concave portions of the protective film base 170 and
the adhesive layer 180.
In an alternative embodiment of the present invention, the
protective film base 170 may include the plurality of cavities B
having a first shape and a plurality of second cavities having a
second shape different from the first shape. For example, the
plurality of cavities B may be concave from the first surface M1 of
the protective film base 170, and the plurality of second cavities
may have a circular shape. The plurality of second cavities may be
spaced between the plurality of cavities B and apart from the first
surface M1 of the protective film base 170.
Referring to FIGS. 7 and 8, a display apparatus according to an
exemplary embodiment of the present invention may include a
protective film base 170 including a first protective film base
layer 171 and a second protective film base layer 173. The first
protective film base layer 171 and the second protective film base
layer 173 may include a plurality of first cavities B1 and a
plurality of second cavities B2, respectively, and may be
sequentially stacked. The protective film base 170 may include one
layer as in the above-described exemplary embodiments of the
present invention, or may be formed by stacking two or more layers,
as shown in FIG. 7. Although FIG. 7 shows a case where the
protective film base 170 includes the first protective film base
layer 171 and the second protective film base layer 173, the
present invention is not limited thereto. For example, the
protective film base 170 may include three or more layers. In this
case, at least one of the first protective film base layer 171 and
the second protective film base layer 173 may include an opening
corresponding to a bending area BA. FIG. 7 shows a case where an
opening is formed in the second protective film base layer 173. In
the protective film base 170, the thickness of a stress
concentration area 170A corresponding to the bending area BA may be
adjusted by using an opening formed in the first protective film
base layer 171 or the second protective film base layer 173. For
example, a thickness of the first protective film base layer 171
and the second protective film base layer 173 in the peripheral
area is greater than a thickness of the first protective film base
layer 171 in the stress concentration area 170A. As a result, a
tensile stress generated during bending may be reduced.
In addition, each of the first cavities B1 and each of the second
cavities B2 may have the same size and/or shape, but are not
limited thereto. Each of the first cavities B1 and each of the
second cavities B2 may have different sizes and/or shapes, and
positions at which the first cavities B1 are arranged may be
different from positions at which the second cavities B2 are
arranged.
The first protective film base layer 171 may include a first
surface M1 in contact with an adhesive layer 180, and the second
protective film base layer 173 may include a second surface M2 in
contact with the first protective film base layer 171. The first
surface M1 may include a plurality of first concave portions
concaved in the direction of the first protective film base layer
171, and the first cavities B1 may be the plurality of first
concave portions. For example, the first cavities B1 may be spaces
between the first protective film base layer 171 and the adhesion
layer 180. In addition, the second surface M2 may include a
plurality of second concave portions concaved in the direction of
the second protective film base layer 173, and the second cavities
B2 may be the plurality of second concave portions. For example,
the second cavities B2 may be spaces between the second protective
film base layer 173 and the first protective film base layer 171.
As shown in FIG. 7, the first cavities B1 and the second cavities
B2 may all be spaces between concave grooves and an upper layer. In
an exemplary embodiment of the present invention, one selected from
each first cavity B1 and each second cavity B2 may be a space
between a concave groove and the upper layer, and the other may
include a bubble arranged therein and spaced apart from the first
surface M1 or the second surface M2. In an exemplary embodiment of
the present invention, both the first cavity B1 and the second
cavity B2 may include a bubble arranged therein and spaced apart
from the first surface M1 or the second surface M2.
Referring to FIG. 8, the first cavities B1 are formed to extend in
the first direction in the first protective film base layer 171,
and the second cavities B2 are formed to extend in the second
direction in the film base layer 173. In other words, the first
surface M1 may include a plurality of first concave portions that
are concave in the direction of the first protective film base
layer 171 and extend in the first direction. The first cavities B1
may be spaces between the plurality of first concave portions and
the adhesive layer 180. In addition, the second surface M2 may
include a plurality of second concave portions that are concave in
the direction of the second protective film base layer 173 and
extend in the second direction. The second cavities B2 may be
spaces between the plurality of second concave portions and the
first protective film base layer 171. In this case, the first
direction and the second direction may be different from each
other. In an exemplary embodiment of the present invention, as
shown in FIG. 8, the first direction and the second direction may
be orthogonal to each other, but the present invention is not
limited thereto.
As described above, in the display apparatus according to exemplary
embodiments of the present invention, a protective film arranged on
a lower surface of a substrate may include a plurality of cavities
to absorb external impacts or disperse directions of forces, and
thus, it is possible to reduce an occurrence rate of a defect in
the process of manufacturing the display apparatus and to reduce
manufacturing costs.
According to exemplary embodiments of the present invention, it is
possible to provide a display apparatus capable of reducing a
manufacturing cost and an occurrence rate of a defect in the
process of manufacturing the display apparatus.
While the present invention has been described with reference to
exemplary embodiments thereof, it will be understood by those of
ordinary skill in the art that various changes in form and details
may be made thereto without departing from the spirit and scope of
the present invention as defined by the following claims.
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